Structured Abstract/Summary " Relation to a research objectives in the FOA. The study addresses the Centers for Disease Control and Prevention priority areas of healthy communities, healthy children, and achieving public health equity. It is responsive to the National Center for Injury Prevention and Control Funding Opportunity Announcement research objectives of exploratory and developmental research that will expand and advance our understanding of causes and approaches to prevent unintentional injury among children, research into the cost-effectiveness of policies to prevent transportation injuries to children, and opportunistic evaluations of changes in environments that could influence the rate of unintentional childhood injuries. " Importance. In the United States, injury exacts a greater toll in potential years of life lost than cancer and cardiovascular disease combined. Injuries tend to afflict the youngest members of society, and no child is more at risk of serious injury than the pediatric pedestrian. In one estimate 50,000 children in the U.S. are struck by cars each year with 1,800 dying " Objectives. Our overarching goal is evaluate the effectiveness of a large-scale federally-funded Safe Routes to School (SRTS) transportation initiative of safety improvements to the built environment surrounding public schools to prevent pediatric pedestrian injuries. We will test the hypotheses that (1) changes to the built environment are associated with significantly decreased risk of pediatric pedestrian injury occurrence and severity, and (2) the probability of pediatric pedestrian injury is significantly lower in SRTS areas than in non- SRTS areas. " Design. We propose to conduct what is essentially a natural epidemiological experiment through the opportunistic evaluation of a changes in the build environment to prevent and control child pedestrian injury. The study will be based on the secondary analyses of administrative law enforcement and health data sets using time series methods, Poisson regression and Bayesian hierarchical spatial modeling. " Setting. High population and traffic dense urban environments. " Participants. Children under the age of 18. " Interventions. Capital improvements including new traffic and pedestrian signals, the addition of exclusive pedestrian crossing times, speed bumps, speed boards, high visibility crosswalks and new parking regulations at 135 of New York City's 1471 public schools. " Outcomes. The project will result in the evaluation of a large-scale injury control and prevention initiative, the wider dissemination of the best available evidence on cost-effective changes to the built environment in urban settings, and the development and translation of a set of epidemiological tools utilizing recent innovative advances in evidence synthesis and spatiotemporal disease mapping to prevent and control pediatric pedestrian injuries. PUBLIC HEALTH RELEVANCE: Our overarching goal of this study is to conduct an opportunistic epidemiologic evaluation of the effectiveness of a large-scale federally-funded Safe Routes to School (SRTS) transportation initiative of safety improvements to the built environment surrounding public schools to prevent pediatric pedestrian injuries.